Grinders



July 26, 1960 J. K. ELY 2,946,163

GRINDERS Filed May 1, 1958 Unite rates atent O GRINDERS James K. Ely, Pittsburgh, Pa., assignor to Allegheny Ludlum Steel Corporation, Brackenridge Pa., a corporation of Pennsylvania Filed May 1, 1958, Ser. No. 732,217

8 Claims. (Cl. 51-188) This invention relates to the polishing and grinding of metals and particularly togrinders and polishing and grinding belts employed in the surface preparation of flat rolled metal products.

In the manufacture and processing of flat rolled metal products it is frequently desirable and sometimes necessary to provide a predetermined ground or polished finish to the surface of the metal. Such a finish is often desirable to minimize the necessity of metal finishing of subsequently fabricated articles or may be desirable from the standpoint of removing unattractive or unsound surface conditions frequently resulting from descaling and heat treating practices. For example, stainless steel cold rolled sheets are commonly polished on endless grinder belts having an abrasive material of from about 120 to 150 grit size on the surface thereof to obtain what is known as a No. 4 finish. Such a finish is not only popular, but also is a required intermediary step in securing even finer finishes which are commonly obtained by subjecting the sheet to further polishing and grinding operations. The fabrication of titanium and titanium alloy flat strip and sheet also requires surface preparation involving a grinding and polishing with various size grit materials.

Metal sheets are conventionally ground and polished by passing them through grinding and polishing machines which impress upon-their surfaces continuously traveling endless grinding and polishing belts. These belts are propelled over the fiat surfaces of sheets by means of motivated rolls. The abrasive surface of the grinding and polishing belts consists of an abrasive material bonded to the surface of the belt of the size required to obtain the desired finish. Such grinding belts may be purchased on the open market in a wide variety of widths and sizes; however, grinding machines are generally designed to accommodate a belt of a predetermined width. So long as the metal sheets being ground or polished are of a width that requires the maximum width belts that the rolls of the machines will accommodate, an eflicient use of the abrasive surface is experienced. However, the metals industry in responding to a variety of orders must frequently polish and grind metal sheets of substantially less width than the maximum width that may be employed in the polishing and grinding machines. It would follow that to polish narrower sheets one should employ narrower polishing belts to conserve the use of abrasives. However, such is not possible in that if belts of less than the maximum predetermined Width are employed, such narrow belts wear into the surface of the rolls supporting the grinding belt at the belt edges with the result that wider belts may not be used thereafter to polish wider sheets without changing the polishing roll of the grinding machine. The grooves caused by the wearing in of the narrow width belts on wide rolls prohibit the use of the wide belts on these rolls to polish the wider sheets because if the grooved rolls are so employed, defects or undesirable marks will occur on the Wider sheets in the locality of such grooves.

, 2,946,163 Patented July 26, 1960 Although the grooving effects of polishing belts are no problem where the same size of belts is always employed, it can be seen that where various width belts are used unmarred, polished and ground sheets can only be secured for the narrowest width of sheet that has been previously accommodated. For example, where it is desired to grind a 40-inch sheet, which for practical pur- 7 the grooves imparted to the rolls by the 44-inch belt make it imposible for the rolls to thereafter uniformly support the wider belts. The time and expense involved in changing rolls on such machines is even more inefficient and wasteful than the waste of large amounts of abrasive surface. Such waste of abrasive materials is common in the metal finishing industry today.

In the copending application Serial No. 712,511 of Daniel W. Heck, filed Ian. 31, 1958, and assigned to the assignee of this invention, a means of overcoming the difiiculties enumerated hereinbefore is disclosed and claimed. Such means includes the use of flexible tapes applied lengthwise of and secured to at least a portion of the back of the more narrow grinder belt so as to extend beyond each of the edges of the belt. While the said Heck invention is a definite solution to the problem of scoring of the grinder rolls where the narrow belts are utilized and is used extensively at the present time, it will be appreciated that in use the application of such flexible tapes presents problems of application, particularly where the flexible tape carries a pressure-sensitive adhesive over the entire areaof one of the surfaces thereof. Further, such flexible tapes are usually applied in the mill where the grinders are being utilized, thereby necessitating delays in the use of the grinders, and if the grinder belts are to be stored between uses such flexible tapes are often damaged.

In accordance with the present invention, grinding and polishing belts of various widths may be freely employed to grind the surface of metal sheets of variouswidths without afiecting or destroying the usefulness of the rolls employed in propelling such belt, and without the disadvantages referred tohereinbefore with respect to the outstanding Heck invention.

An object of this invention is to provide for utilizing various widths of grinding and polishing belts on polishing and grinding machines without damaging the rolls of said machines.

Another object of this invention is to provide a belt of the grinding and polishing type that will not groove the rolls of grinding and polishing machines.

A further object of this invention is to provide an integral belt of the grinding and polishing type having flexible edges for protecting the rolls of grinding and -polishing machines.

Other objects of this invention will become apparent from the following description when taken in conjunction with the accompanying drawing in which:

Figure 1 is a view in elevation with parts broken away of a grinding and polishing belt constructed in accordance with the present invention;

Fig. 2 is a view in cross section of the belt of Fig. 1, and

Fig. 3 is a schematic illustration of a grinding and polishing machine adapted to utilize the belt of Figs. 1 and 2;

Referring to the drawing, and in particular to Figs. 1 and 2, there is illustrated a grinding belt 10 that embodies the teachings of this invention, the break-away area 12 illustrating that the belt may be of comparatively greater or less width than shown. In the embodiment illustrated, the belt 19 is of the loop or endless type and may be of any predetermined length and comprises an abrasive surface formed of suitable abrasive material 14 secured as by means of a suitable adhesive to a backing 16 formed of a plurality of layers or laminations 18 of fibrous material such as paper, cloth, woven fabric or the like which may be impregnated with a resin or the layers may be otherwise secured together as by means of a suitable adhesive to form an integral body.

As illustrated, one or more layers 25? forming the underside of the backing to are of a width somewhat greater than the width of the layers adjacent the abrasive surface and extend beyond the edges of such abrasive surface for a predetermined distance of from /8 to 1 inch to form flexible edges 22 on the underside of the belt 10 and coextensive with the length of the belt. Such flexible edges 22 are thus in the same plane and coextensive with the underside of the belt it).

In practice, the backing 16 may be readily formed of layers of Bil-pound paper or of woven cotton cloth impregnated with a stiffening material or a combination of paper and cloth layers as in common practice. Where the belts have been previously formed of plies or layers of Bil-pound paper, the same number of plies may be used in making the belt of this invention, it being noted that the two plies adjacent the underside are cut to have a width as stated hereinbefore in excess of the layers forming the abrasive surface. Likewise, where woven cotton cloth is utilized as the fibrous material, at least the bottom layer forrrung the underside of the belt is cut to extend beyond the edges of the layers forming the support for the abrasive surface. As will be appreciated, the abrasive material 14 may be any hard particulate material. such as alumina or silicon carbide or mixtures thereof and may have a grit size ranging from 16 grit through 600 grit, depending on the finish desired, such abrasive material 14 being secured to the surface of the belt as by means of an animal hide glue or the like.

Referring to Fig. 3, the belt it of this invention is illustrated as used in a conventional grinding machine 24 for the grinding of a sheet 26 of metal such as stainless steel or the like. The machine 24 is provided with a plurality of supporting and driving rolls 28, 34 52 and 34 for propelling the belt 19, roll 28 being disposed to be driven by a motor 36 that is connected to a suitable source of supply. The drive roll 28 is constructed of a steel core 38 and is provided with a rubber case or sheath 40 having serrations (not shown) thereon for efiiciently gripping and driving the belt 10. The rolls 3% and 32 are steel guide and tension rolls being of slightly greater diameter near the center of such rolls to aid in guiding the belt, it being noted that roll 30 is spring biased as by spring 42 to maintain tension on the belt. The roll 34 is a pressure roll disposed to maintain the belt 16 in an abrasive relation with the sheet 26. Such roll 34 is also formed of a steel core 44 and a serrated rubber case or sheath 46 thereon for engaging the belt 1%). In general the sheet 26 is retained in position relative to the driven grinding belt 19 by means of opposed guide rolls 43 on either side of the grinding area while being supported on additional rollers 50 and a steel backing roll 52, the latter being disposed opposite the roll 34 of the grinder.

In practice, as an abrasive operation is performed on the sheet 26 and the belt 16 is driven over the rolls 23, 30, 32 and 34 with the abrasive surface in a grinding or polishing engagement with the sheet 26, it is found that the flexible edges 22 which extend beyond the main body portion of the belt distribute the pressure of the edge of the belt over a wider area of the rolls and prevent wear or abrading of the rolls and in particular the rubber covered roll 34 which maintains the belt in abrasive engagement with the sheet 26. Because of the presence of the flexible edges 22 on the belt 10 it is apparent that such edges must wear away before the pressure applied -through the main body portion of the belt is applied directly to the roll 34 in a localized area corresponding to the edges of the more narrow'laminations of the abrasive supporting layers and that before such a condition will be encountered the abrasive material of the belt will be worn away. In practice, it is found that regardless of the size of the grinding belt or of the type of grinding machine utilized, no edge wear or grooving .of the rolls of the grinding machine is encountered where the belt is formed having the flexible edges 22 formed as extensions of the underside layer or layers of the belt.

From the foregoing it is quite apparent that narrow grinder belts embodying the flexible edges 22 can be readily interchanged for other belts of a predetermined wider width normally used on a given grinder without scoring of the rolls of the grinder, thus making it possible to use such rolls with a wide variety of belts of different widths. No excess of lost time is encountered in exchanging the belts of different widths since the flexible edges 22 are an integralpart of each belt so used in preventing the scoring of the rolls. Further, storage of the grinder belts having such flexible edges presents no problem since the flexible edges are integral with the belt and the exposed surfaces of such flexible edges are free.

of pressure-sensitive adhesive.

I claim:

1. In a belt grinder having rolls adapted to utilize an endless belt of the grinding and polishing type having a predetermined width, the combination therewith of, an endless belt of the grinder and polishing type having a width less than said predetermined width, said belt being formed of a plurality of layers of fibrous material integrally secured together throughout their adjacent surfaces and having an outer and underside surface, an abrasive material carried on said outer surface layer, at least the layer forming the underside surface of the endless belt being of a width greater than the width of said outer surface layer, said underside surface layer being disposed to extend'beyond each of the edges of said outer surface layer to form flexible edges integral with the belt disposed to engage the rolls of the grinder and prevent scoring thereof whereby the rolls may be later used with a belt having said predetermined width.

2. in a belt grinder having rolls adapted to utilize an endless belt of the grinding and polishing type having a predetermined width, the combination therewith of, an endless belt of the grinder and polishing type having a width less than said predetermined width, said belt being formed of a plurality of layers of fibrous material impregnated with a binder and integrally secured together throughout their adjacent surfaces to provide an outer and underside surface on the belt, an abrasive material carried on said outer surface layer, at least the layer forming the underside surface of the endless belt being of a Width greater than the width of said outer surface layer, said underside surface layer being disposed to extend beyond each of the edges of said outer surface layer to form flexible edges coextensive with the length of the belt and integral therewith and disposed to engage the rolls of the grinder to prevent scoring thereof whereby the rolls may be later used with a belt having said predetermined width.

3. In a belt grinder having rolls adapted to utilize an endless belt of the grinding and polishing type having a predetermined width, the combination therewith of, an endless belt of the grinder and polishing type having a width less than said predetermined width, said belt being formed of a plurality of layers of fibrous material integrally secured together throughout their adjacent surfaces and having an outer and underside surface, an abrasive material carried on said outer surface layer, at

least the layer forming the underside surface of the endless belt :being of a width greater than the width of said outer surface layer, said underside surface layer being disposed to extend beyond each of the edges of said outer surface layer for a distance of between inch and 1 inch to form flexible edges integral with the belt disposed to engage the rolls of the grinder and prevent scoring thereof whereby the rolls may be later used with a belt having said predetermined width.

4. A belt of the polishing and grinding type comprising, a continuous belt formed of a plurality of layers of fibrous material integrally secured together throughout their adjacent surfaces and having an outer surface and an underside surface, abrasive material carried on the outer surface layer, at least the layer forming the underside surface being of a width greater than the width of the outer surface layer and being disposed to extend beyond the edges of said outer surface layer to form integral flexible edges on the endless belt that are coextensive with said underside surface layer and throughout the length of the belt.

5. A belt of the polishing and grinding type comprising, a continuous belt formed of a plurality of layers of fibrous material impregnated with a binder and integrally secured together throughout their adjacent surfaces to provide an outer surface and an underside surface on the belt, abrasive material carried on the outer surface layer, at least the layer forming the underside surface being of a width greater than the width of the outer surface layer, said underside surface layer being disposed to extend beyond the edges of said outer surface layer to form flexible edges on the endless belt that are coextensive with said underside surface throughout the length of the belt.

6. A belt of the polishing and grinding type comprising, a continuous belt formed of a plurality of layers of fibrous material integrally secured together throughout their adjacent surfaces, a predetermined number of said layers having a predetermined width for forming an outer surface portion, abrasive material carried on the outer surface portion, the remainder of the layers being disposed to form an underside surface portion, the underside surface portion of the layers being of a width greater than the width of the layers of the outer surface portion and being disposed to extend beyond the edges of the outer surface portion to form flexible edges on the endless belt that are coextensive with the layers of the underside surface portion throughout the length of the belt.

7. In a belt grinder having rolls adapted to utilize an endless belt of the grinding and polishing type having a predetermined width, the combination therewith of, an

endless belt of the grinder and polishing type having a width less than said predetermined width, said belt being formed of a plurality of layers of fibrous material integrally secured together throughout their adjacent surfaces, a predetermined number of said layers having a predetermined width for forming an outer surface portion, an abrasive material carried on said outer surface portion, the remainder of said layers being disposed to form an underside surface portion, said underside surface portion of the layers being of a width greater than the width of the layers of the outer surface portion and being disposed to extend beyond each of the edges of said outer surface portion to form flexible edges coextensive with said underside surface portion and integral with the belt disposed to engage the rolls of the grinder and prevent scoring thereof whereby the rolls may be later used with a belt having said predetermined width.

8. In a belt grinder having rolls adapted to utilize an endless belt of the grinding and polishing type having a predetermined width, the combination therewith of, an endless belt of the grinder and polishing type having a width less than said predetermined width, said belt being formed of a plurality of layers of fibrous material impregnated with a binder and integrally secured together throughout their adjacent surfaces, a predetermined number of said layers having a predetermined width for forming an outer surface portion, an abrasive material carried on said outer surface portion, the remainder of said layers being disposed to form an underside surface portion, said underside surface portion of the layers being of a width greater that the width of the layers of the outer surface portion and being disposed to extend beyond each of the edges of said outer surface portion a distance of between ,4 inch and 1 inch to form flexible edges coextensive with said underside surface portion and integral with the belt disposed to engage the rolls of the grinder and prevent scoring thereof whereby the rolls may be later used with a belt having said predetermined width.

References Cited in the file of this patent UNITED STATES PATENTS 305,068 Fullerton Sept. 16, 1884 348,177 Totman Aug. 24, 1886 810,037 Clemons Jan. 16, 1906 1,288,908 Johnson Dec. 24, 1918 2,145,418 Herchenrider- Jan. 31, 1939 2,320,139 Kirchner May 25, 1943 2,422,876 Allred June 24, 1947 

